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authorMarti Bolivar <mbolivar@mit.edu>2010-10-20 06:46:52 -0400
committerMarti Bolivar <mbolivar@mit.edu>2010-10-20 06:46:52 -0400
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+.. _arduino-delay:
+
+delay()
+=======
+
+Description
+-----------
+
+Pauses the program for the amount of time (in miliseconds)
+specified as parameter. (There are 1000 milliseconds in a second.)
+
+
+
+Syntax
+------
+
+delay(ms)
+
+
+
+Parameters
+----------
+
+ms: the number of milliseconds to pause (*unsigned long*)
+
+
+
+Returns
+-------
+
+nothing
+
+
+
+Example
+-------
+
+::
+
+ int ledPin = 13; // LED connected to digital pin 13
+
+ void setup()
+ {
+ pinMode(ledPin, OUTPUT); // sets the digital pin as output
+ }
+
+ void loop()
+ {
+ digitalWrite(ledPin, HIGH); // sets the LED on
+ delay(1000); // waits for a second
+ digitalWrite(ledPin, LOW); // sets the LED off
+ delay(1000); // waits for a second
+ }
+
+
+
+Caveat
+------
+
+While it is easy to create a blinking LED with the delay()
+function, and many sketches use short delays for such tasks as
+switch debouncing, the use of delay() in a sketch has significant
+drawbacks. No other reading of sensors, mathematical calculations,
+or pin manipulation can go on during the delay function, so in
+effect, it brings most other activity to a halt. For alternative
+approaches to controlling timing see the
+`millis() <http://arduino.cc/en/Reference/Millis>`_ function and
+the sketch sited below. More knowledgeable programmers usually
+avoid the use of delay() for timing of events longer than 10's of
+milliseconds unless the Arduino sketch is very simple.
+
+
+
+Certain things *do* go on while the delay() function is controlling
+the Atmega chip however, because the delay function does not
+disable interrupts. Serial communication that appears at the RX pin
+is recorded, PWM
+(`analogWrite <http://arduino.cc/en/Reference/AnalogWrite>`_)
+values and pin states are maintained, and
+`interrupts <http://arduino.cc/en/Reference/AttachInterrupt>`_ will
+work as they should.
+
+
+
+See also
+--------
+
+
+- `millis <http://arduino.cc/en/Reference/Millis>`_\ ()
+- `micros <http://arduino.cc/en/Reference/Micros>`_\ ()
+- `delayMicroseconds <http://arduino.cc/en/Reference/DelayMicroseconds>`_\ ()
+- `Blink Without Delay <http://arduino.cc/en/Tutorial/BlinkWithoutDelay>`_
+ example
+